1. Field of the Invention
This invention relates to a tethered-ball training device that can be used for repetitive training exercises in a variety of ball sports.
2. Description of the Prior Art
In sports, the player is greatly benefitted by repetitive training of the particular motions required in the sport. With ball sports, however, repetitive exercises are hampered by the requirement for retrieving the ball after each execution of a particular exercise. There are several means of coping with ball retrieval, the most simple being to confine the ball in a small enclosure or with the aid of a backboard of some sort. For example, batters can bat in a small cage, and tennis serves can be practiced against a wall. However, even this method requires the trainee to spend some time retrieving balls. Complicated automatic ball retrieval and projectile systems, such as might be found in a batting cage, are available, but these devices tend to be large and expensive and hence not readily accessible for general use.
Another option is to tether the ball in some fashion so that its range of motion is restricted. The use of elastic tethers ensures that the ball will eventually return to rest in the starting position, albeit with considerable rebound action. Tethered-ball training devices can be simple, portable and relatively inexpensive.
A very simple tethered-ball device is described in U.S. Pat. No. 4,948,150. The ball hangs via an elastic cord from an inverted-L-shaped support means. A horizontal surface at the tether point coupled to a flexible vertical rod acts to dampen the kinetic energy imparted by striking the ball. The horizontal surface also functions as a rebound surface and prevents the elastic cord and ball from wrapping around the horizontal support means. The entire device is attached to a net pole or a wall at a fixed height.
A similar example is described in U.S. Pat. No. 3,716,235. The ball hangs from an inverted-U-shaped support means between the two vertical poles. The ball is tethered via an elastic cord and the tether is pivotally mounted to the horizontal pole so that when the ball is struck, the ball and tether freely rotate around the horizontal pole, rather than wrapping around it. The vertical poles are telescoping, allowing the height of the ball to be varied. However, since the device is mounted to a wall or ceiling, adjusting the height of the ball would require a ladder.
Both of these devices are mounted to an existing surface, such as a wall, ceiling, net pole or net. Thus, these devices cannot be used in places where no readily available attachment surface is available. There are, however, a number of free-standing tethered-ball training tools, such as are described in U.S. Pat. Nos. 5,062,946 and 4,647,042. In general, these devices consist of a tethered-ball attached to an inverted-L-shaped support means that stands on the floor via a large base. No means of preventing the ball and tether from wrapping around the poles is provided in U.S. Pat. No. 4,647,042, but in U.S. Pat. No. 5,062,946, the tether is allowed to rotate freely about the horizontal pole by virtue of a pivotal mounting system. Both systems provide for adjusting the height of the ball by adjusting the length of the vertical pole.
In all of these systems, the ball is tethered via a flexible cord, generally made of an elastic material. Thus, all of the devices suffer from excessive rebound reaction of the ball when forcibly struck. There is considerable risk that the ball may rebound and strike the player. Additionally, it may take considerable time for the ball to come to rest, as it will likely rebound several times before stopping.
The use of a vertical elastic tether allows the ball to move vertically and horizontally within the limits of the tether. Although the tether itself may be pivotally mounted to the horizontal support means and thus the ball is free to rotate around the horizontal bar, the ball could also wrap around the vertical support or strike the vertical support and rebound to strike the player unless the tether is sufficiently short.
The problem of too much horizontal mobility has been addressed in U.S. Pat. No. 4,881,742 in an interesting way. Instead of employing a flexible cord as a tether, this device uses a semi-rigid tether pivotally connected to the horizontal pole. Because the tether is semi-rigid, the ball is generally limited in motion to a vertical plane. Thus, sideways movement of the ball is restricted, increasing the safety of the device. However, the use of a semi-rigid tether interferes with the player freely striking the ball, especially in a downward direction, and thus presents its own hazards.
Other rigid tether devices have been described. U.S. Pat. No. 5,499,812 describes a cam arm apparatus wherein the ball is attached to a horizontal rod which rotates about a vertical support rod. Thus, the ball is only free to rotate in a horizontal plane. The cam arm operates to ensure that the ball returns to its original position after being struck. This device is disadvantageous in that the ball cannot be struck in an upward or downward direction. Further, the rigid arm presents some risk to the player who may strike it accidentally. Additionally, the device is heavy, complicated and expensive.
One of the problems with all vertically tethered devices is that the tether itself interferes with a downward strike of the ball. Downward strikes are important in many sports. For example, the spike and the serve in volleyball both require a downward stroke, as does the serve of tennis. Thus, vertically tethered devices are limited in this respect. One means of allowing the player to practice a downward stroke is to support the ball from two points in a horizontal plane. This idea was employed in U.S. Pat. No. 3,897,950. The device disclosed therein employs two horizontal rods ending in soft cups that hold the ball. The ball can be freely struck in a downward direction, causing the poles to move aside and allow the ball to travel freely away from the player. The player must reload the device for the next stroke however, because the ball is not tethered. Further, the player is still at risk for striking the rigid horizontal poles or cups.
A two point attachment, tethered-ball system has also been devised. U.S. Pat. No. 4,372,561 describes a ball supported by two horizontal elastic tethers. The tethers are mounted between two vertical poles that are attached to a net or other surface. Because the ball is attached in two places, it cannot wrap around either pole. However, in allowing for complete freedom of vertical movement, the ball has been restricted horizontally. Thus, the player receives no feedback about his horizontal aiming ability. Further, the device cannot be used where an attachment surface is lacking, for example, in many outdoor locations.
Therefore, what is needed in the art is a tethered-ball training device that provides maximum freedom in the horizontal and vertical planes, yet prevents the ball and tether from becoming entangled in the support means. It would also be advantageous to have a tethering means that does not allow the ball to forcefully rebound towards the player or otherwise present a hazard to the player. Likewise, the ball should not take a long time to come to rest in its starting position. None of the existing tethered-ball devices allow a player to know how well the ball has been directed by his strike, since the motion of the ball is necessarily restricted by the tether. The ideal device would provide feedback to the player as to whether a ball has been directed in or out of bounds and the speed of ball travel. The ideal device would also be freestanding, fully portable, lightweight and inexpensive.
These and other advantages of the present invention will become apparent from the following detailed description.